Manage attributes

Analytica User GuideWorking with Large ModelsManage attributes

Every node in an Analytica model is described by a collection of attributes. For some models, you might want to control the display of attributes or create new attributes. Some attributes apply to all classes (variable, module, and function). Others apply to specific classes, as listed in the following table.

Attribute	Function	Module	Variable
Author		*
Check	+		+
Class	*	*	*
Created		*
Definition	*		*
Description	*	*	*
Domain			+
File Info		*
Help	+	+	+
Identifier	*	*	*
Inputs	+		+
Last Saved		*
MetaOnly			+
Outputs	+		+
Parameters	*
Probvalue			+
Recursive	+
Title	*	*	*
Units	*		*
Value			+
User-created (up to 5)	+	+	+

Key:

plain = modifiable by user

italic = set by Analytica

* = always displayed

+ = optionally displayed

For descriptions of the attributes, see Glossary.

Attributes dialog

Use the Attributes dialog to control the display of optional attributes in the Object window and Attribute panel and to define new attributes. To open the Attributes dialog, select Attributes from the Object menu.

• Class popup menu

Use this menu to select the Attribute list for variables, modules, or functions.

• Attribute list

This list shows attributes for the selected class. Attributes with an asterisk (*) are always displayed in the Object window and Attribute panel. Attributes with a checkmark (√) are displayed optionally

Displaying optional attributes

To display an optional attribute in the Object window and Attribute panel, click it once to select it, then click it again to show a checkmark. To hide an optional attribute, click it once to select it, then click it again to remove the checkmark.

Creating new attributes

You can create up to five additional attributes. For example, you could use a reference attribute to include the bibliographic reference for a module or variable.

To create a new attribute in the Attributes dialog:

1. Select new Attribute from the attribute list to show the new Attribute Title field and the Create button.
2. Enter the title for the new attribute in the Title field. The title can contain a maximum of 14 characters; 10 characters are the maximum recommended for visibility with all screen fonts.
3. Click the Create button to define the new attribute.

A newly created attribute is displayed for modules, variables, and functions. To control whether or not it is displayed for modules, variables, or functions, select the Class popup menu in the Attributes dialog, and turn the checkmark on or off.

Renaming an attribute

To rename a created attribute:

1. Select it in the Attribute list. The Title field and the Rename button appear.
2. Edit the name of the attribute in the Title field.
3. Click the Rename button.

Referring to the value of an attribute

Analytica includes the following function for referring to the value of an attribute in a variable’s definition.

Attrib Of x

Returns the value of attribute attrib of object x, where x might be a variable, function, or module. For most attributes, including Identifier, Title, Description, Units, Definition, and user-defined attributes the result is a text value. For Value and Probvalue, the result is the value of the variable (deterministic or probabilistic, respectively). For Inputs, Outputs, and Contains (an attribute of a module), the result is a vector of variables.

You cannot refer to an attribute of a variable by naming the variable in the definition of that variable. Instead, refer to it as Self, for example:

 Variable Boiling_point
 Units: F
 Definition: If (Units of Self) = 'C'
                THEN 100 ELSE 212
 Boiling_point → 212 

Library: Special

Example: Units of Time → 'Years'

Tip

Changes to attributes other than Definition do not automatically cause recomputation of the variables whose definitions refer to those attributes. So, if you change Units of Boiling_point to C, the value of Boiling_point does not change until Boiling_point is recomputed for some other reason.

See Also

Finding variablesManage attributesInvalid variables